1. Field of the Invention
This invention relates to the field of vehicles. More specifically, the invention comprises a display and control system for various vehicle devices that utilizes a touch screen as its primary operator interface.
2. Description of the Related Art
Modern vehicles include a wide variety of devices that are typically controlled by a human operator. Examples include audio components, blower fans, window motors, seat position motors, and mirror positioning motors. Many of these components have been traditionally controlled with a switch that selectively supplies current to a motor. Other components have been traditionally controlled using a rheostat. In recent years, however, digital interfaces have begun to dominate.
FIG. 1 shows a perspective view of a typical prior art vehicle interior—in this case a passenger car. Vehicle 10 includes center console 12 and dash 14. Factory radio 16 is mounted in the center console. It includes various buttons allowing the user to control the radio functions. For the particular car shown, environmental controls 18 are located immediately below the radio. The environmental control panel includes buttons allowing the user to select a cabin temperature, a fan speed, and various vent configurations.
Steering wheel 20 may also incorporate additional input features such as steering wheel controls 22. The steering wheel controls in this case allow the user to change the radio volume, change the audio source selected, change the vehicle's “cruise control” settings, and possibly control a cellular telephone. There is therefore some redundancy in the switching features. As an example, the user may reach over to the center console or the user may employ the switches on the steering wheel itself to control many of the same functions.
Until recent times the typical control switch was wired in series with the device it controlled. For example, a seat control switch simply “made” the power circuit to a motor driving the relevant portion of the seat for as long as the switch was closed. Other switches controlled the low-current side of a relay but the principle of operation was essentially the same. More complex switches were used for such devices as power mirrors, but the principle of operation was again the same for these devices as well. This is no longer the case, however, as the control of automotive components is rapidly shifting to the digital domain.
The general implementation of digital control uses a data bus distributed throughout the vehicle. The data bus sends digital messages (such as the state of a controlling switch) that may be received by any component connected to the bus. The data bus does not provide electrical power to the actuating components such as a seat motor (though it may supply some low level power to other devices). Power is supplied separately to the actuating components through a power distribution harness.
As far as the user is concerned, the new digital paradigm often appears to function just like the old analog paradigm. As an example, if the user wishes to roll down a window, he or she still presses a designated button and the window rolls down. However, the button is not “making” an analog circuit and is not serving as part of the path for the electrical current driving the window motor. Instead, both the button and the motor are hooked up to a data bus, and the data bus is likely hooked up to a controlling microprocessor (sometimes called a “Body Control Unit”). The switch sends a digital message specifying its identity and the fact that the switch is in an “ON” state. The Body Control Unit receives and interprets this message, then makes an appropriate response. In response to the window control button being placed in the “ON” position, the body control unit sends a digital message to the appropriate window motor instructing it to move the window. The window motor has an associated controller that receives and decodes this digital instruction. Power electronics within the window controller then activate a driving motor to move the window.
While the digital approach sounds complicated, it is in many instances much more efficient to install and run than a traditional system. Rather than routing dedicated wiring harnesses from switches to the components they control, the digital approach allows the vehicle manufacturer to provide a single data harness and only a few power harnesses. New components may also be added without the need to add additional wiring.
The first widely-used system implementing the digital paradigm was developed by Robert Bosch, GmbH in the early 1980's. Bosch called its system the “CAN bus,” where “CAN” stands for “Controller Area Network.” Bosch actually released its protocol to the Society of Automotive Engineers with the initial hope of creating a unified communication platform across all vehicle makes and models, though Bosch did not propose to offer the standard free of licensing fees.
The goal of a uniform standard has largely gone unrealized, with the various vehicle manufacturers adopting proprietary systems instead. Even so, the general characteristics of the original CAN standard are found in most vehicle operating protocols. In general, a CAN network is a “masterless” system in which various microcontrollers communicate without the need for one defined “host” computer. This is a significant feature, as a modern vehicle may contain as many as 70 separate electronic control units. The two most significant control units are typically the Engine Control Unit (“ECU”) and the aforementioned Body Control Unit (“BCU”). However, as discussed in the preceding example, each individual window motor is likely to have a separate controller. Other controllers may be provided for a blower fan, an air conditioning compressor, power mirrors, air bags, air-inflated suspension “springs,” an automatic transmission, and even small things like the dimming functions of a rear-view mirror.
The control of the factory audio equipment is now also done using digital commands over a data bus. If a user presses a steering wheel control 22 as shown in FIG. 1, a digital signal is sent along the data bus and the radio responds to that digital signal (such as a “volume up” command). Thus, the steering wheel controls are not connected directly to the audio component. Instead, both are connected to a common data bus.
The CAN bus itself is typically just a twisted-pair (two conductors twisted around a common axis to help cancel unwanted emissions). However, although no universal CAN standard for connectors has evolved, it is common to include the CAN pair in a four-wire cable. The four-wire cable then carries CAN−, CAN+, Power Voltage, and Ground. Using this single connector thereby allows the simultaneous connection of a component to the control bus and the power distribution bus.
FIG. 2 presents a very simple depiction of a CAN bus and other components that may be connected to it. A Body Control Unit (“BCU”) monitors the CAN bus and, in this instance, provides a conduit to the Engine Control Unit (“ECU”). An OEM audio component (“factory radio”) and OEM navigation component are connected to the CAN bus. Sensors and Switches are also connected to the CAN bus. Only four components are shown but modern vehicles typically have over one hundred individual components connected to a CAN bus.
FIG. 3 presents a simple depiction of several components and their electrical connections to both the CAN bus and the power harness. Each component (blower motor, window motor. seat motor, defrost actuator, window control switch, etc.) is connected in parallel to the CAN bus. In addition, each component needing power is connected to a power harness. Those skilled in the art will know that a single power harness will likely not be used, and that FIG. 3 is therefore overly simplistic. In most cases a high-current device like a blower motor will not be connected to the same power distribution bus as a low-current device like a window switch. However, FIG. 3 serves well to illustrate the general operating principles.
There are a wide variety of CAN interface products now in use. Many of these products allow the reading of vehicle diagnostic information off the CAN bus. Others allow the use of existing steering wheel controls with aftermarket audio components. While these components make use of the CAN technology, there is much more information available on a vehicle's data network than is typically being used or displayed. The available information varies for each type of vehicle but will often include: vehicle speed, engine speed, throttle position, gear selected, longitudinal acceleration, lateral acceleration, manifold pressure, coolant temperature, engine “error codes,” tire pressure. stability control settings. ride height settings. cabin temperature, seat position, mirror position, light status, and bulb status.
In addition, the CAN bus also provides the opportunity to control many more features than the available operator interface may allow. As an example, an experience driver may wish to “override” certain features in specific circumstances. A failed coolant temperature sensor may produce an “overtemp” signal when the engine has just been started and is still cold. In response to this signal some Engine Control Units will restrict the available throttle settings, lock the engine in an idle condition, or actually shut the engine off. An experienced user will realize that a sensor has failed and the “overtemp” condition does not actually exist. It would be advantageous to allow the user to override the automated functions in this scenario, particularly if the vehicle is not in an area where stopping is convenient or safe. It would also be advantageous to allow the user to call up and display an oil temperature sensor (if available) as a proxy for the engine's coolant temperature.
The existing display and control functions, however, are largely stuck in the analog era. In other words, the digital display and control features tend to simply mimic the analog features they replaced. While this allows the driver to easily transition to the new technology, it also represents a lost opportunity for significant enhancement.
Incredibly powerful processors and associated memory devices are now available and affordable. Examples include APPLE's IPAD and comparable tablet devices based on the Android operating system. These devices have the ability to store and run very complex control and monitoring applications. In addition, these devices feature powerful and intuitive user interfaces. The interfaces are typically icon-based touch screens that are infinitely configurable and customizable. The present invention combines the use of these modern devices with the digital environment already in existence on vehicle data buses to unlock the full potential of digital display and control.